Hinges have been and are now primarily fabricated of metals for use on rigid materials in the form of doors, windows, furniture and other products. However, metal hinges are not suitable to connect fabric, vinyl, rubber, paper, leather and the myriad of other natural and synthetic flexible planar materials.
Metal hinges are heavy and require a costly, resource and labor-intensive chain of production processes to manufacture.
Metal hinges corrode and rust, particularly in moist environments. Stainless steel is less corrosive, but substantially more expensive.
Means of attachment of metal hinges to another material or product is limited primarily to the use of metal fasteners such as screws and nails or by direct welding, thus effectively limiting the types of material to which metal hinges may be attached. That is, to other metals, wood, and dense plastics.
Metal piano-style hinges more specifically are costly, not generally available or practical in lengths over eight feet, and most have fixed pins, disallowing the separation of the right and left side flanges from each other. Also, piano-style hinges are not resilient. Should one get bent or folded, it is difficult to return to its original form without damage.
An elongated plastic hinge is disclosed by U.S. Pat. No. 4,231,135 to Fradin, however this hinge is limited to extruded plastic with an extruded cylindrical tubular plastic hinge pin and optional additional rod, also of plastic material.
Manufacture of the Fradin hinge is limited to the use of only one material, extruded plastic, throughout the product, with no provision for layering, embossing, or other structural or aesthetic coupling of like or dissimilar materials.
While the Fradin hinge is flexible, due to the described process of extrusion, it maintains a semi-rigid state when assembled. This, in turn, imposes that rigidity upon the host material or product and limits the application of said hinge to materials compatible with the weight, rigidity, and structure of extruded plastic. Specifically, the Fradin extruded hinge would not be suitable for attachment to most materials lighter in weight or thinner in thickness than itself. For example, many fabrics, plastics, paper and others.
The Fradin hinge is described as sewable. However, the sewing of extruded plastic is realistically limited to industrial machines and not suitable for hand sewing applications. This factor substantially reduces the end uses, users and applications.
The Fradin hinge, with only a single plane flange on either side, can not be attached to a host material or product by enveloping a plane of host material on each of its two surfaces for purposes of added strength, aesthetic symmetry or other purpose.
Fradin and prior art hinges fail to offer material content or physical property options for linear connecting pins and rods other than a like-material tubular extrusion or solid cylindrical rod: metal hinges have metal pins and Fradin's plastic hinge has an extruded plastic tube and rod.
Accordingly, the assembled prior art hinges produce an unyielding cross-section. That is, they are incapable of a flatter relief than the diameter of the rigid tubular knuckles.
Color-matching the Fradin hinge to a solid color material or product to which it is being attached requires custom compounding of plastic pigment prior to extrusion. This is a costly and complicated process and involves purging the extrusion mold after each color. Also, to produce very bright, saturated colors requires a high concentration of pigment which increases cost and may render certain plastics more brittle.
The Fradin hinge, also due to production by extrusion is not capable of being produced in prints or patterns. For example, the same print or pattern as a host material or product.
Fradin and other prior art hinges must be produced separately, then affixed to a second material or product with no provision for the hinge connector being built into the pattern of the end product.
Hinges in present use are unsuited to the option of using only one side of the hinge as a connector. That is, using one side of flange and loops to connect to another product or material.
Although the Fradin hinge embodies a degree of flexibility, a length of several yards would not be capable of, for example, being folded without permanent damage.
Therefore, it is an important object of the present invention to provide an improved flexible hinge connector which satisfies long-felt but as yet unsolved needs and which obviates the aforedescribed disadvantages of the prior art.